/**
 * @created by jiangcheng on 2016-10-15
 * @updated by
 * @description BASE64工具类插件
 */
(function (yufp, window, factory) {
  // 判断是否支持模块定义
  var hasDefine = typeof define === 'function';
  var exports;
  if (hasDefine) {
    // 获取对象
    exports = factory(yufp);
    // 定义模块
    define(exports);
    // 安装插件(兼容非模块的访问方式)
    window.yufp.base64 = exports;
  } else {
    // 获取对象
    exports = factory(yufp);
    // 安装插件
    window.yufp.base64 = exports;
  }
}(yufp, window, function (yufp) {
  var BASE64_MAPPING = [
    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
    'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
    'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
    'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
    'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
    'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
    'w', 'x', 'y', 'z', '0', '1', '2', '3',
    '4', '5', '6', '7', '8', '9', '+', '/'
  ];

  /**
   *ascii convert to binary
   */
  var _toBinary = function (ascii) {
    var binary = [];
    while (ascii > 0) {
      var b = ascii % 2;
      ascii = Math.floor(ascii / 2);
      binary.push(b);
    }

    /*
     var len = binary.length;
      if(6-len > 0){
      for(var i = 6-len ; i > 0 ; --i){
      binary.push(0);
      }
    }*/
    binary.reverse();
    return binary;
  };

  /**
   *binary convert to decimal
   */
  var _toDecimal = function (binary) {
    var dec = 0;
    var p = 0;
    for (var i = binary.length - 1; i >= 0; --i) {
      var b = binary[i];
      if (b == 1) {
        dec += Math.pow(2, p);
      }
      ++p;
    }
    return dec;
  };

  /**
   *unicode convert to utf-8
   */
  var _toUTF8Binary = function (c, binaryArray) {
    var mustLen = (8 - (c + 1)) + ((c - 1) * 6);
    var fatLen = binaryArray.length;
    var diff = mustLen - fatLen;
    while (--diff >= 0) {
      binaryArray.unshift(0);
    }
    var binary = [];
    var _c = c;
    while (--_c >= 0) {
      binary.push(1);
    }
    binary.push(0);
    var i = 0, len = 8 - (c + 1);
    for (; i < len; ++i) {
      binary.push(binaryArray[i]);
    }

    for (var j = 0; j < c - 1; ++j) {
      binary.push(1);
      binary.push(0);
      var sum = 6;
      while (--sum >= 0) {
        binary.push(binaryArray[i++]);
      }
    }
    return binary;
  };

  var __BASE64 = {
    /**
     *BASE64 Encode
     */
    encode: function (str) {
      var base64Index = [];
      var binaryArray = [];
      var i = 0, len = str.length;
      for (; i < len; ++i) {
        var unicode = str.charCodeAt(i);
        var _tmpBinary = _toBinary(unicode);
        if (unicode < 0x80) {
          var _tmpdiff = 8 - _tmpBinary.length;
          while (--_tmpdiff >= 0) {
            _tmpBinary.unshift(0);
          }
          binaryArray = binaryArray.concat(_tmpBinary);
        } else if (unicode >= 0x80 && unicode <= 0x7FF) {
          binaryArray = binaryArray.concat(_toUTF8Binary(2, _tmpBinary));
        } else if (unicode >= 0x800 && unicode <= 0xFFFF) { // UTF-8 3byte
          binaryArray = binaryArray.concat(_toUTF8Binary(3, _tmpBinary));
        } else if (unicode >= 0x10000 && unicode <= 0x1FFFFF) { // UTF-8 4byte
          binaryArray = binaryArray.concat(_toUTF8Binary(4, _tmpBinary));
        } else if (unicode >= 0x200000 && unicode <= 0x3FFFFFF) { // UTF-8 5byte
          binaryArray = binaryArray.concat(_toUTF8Binary(5, _tmpBinary));
        } else if (unicode >= 4000000 && unicode <= 0x7FFFFFFF) { // UTF-8 6byte
          binaryArray = binaryArray.concat(_toUTF8Binary(6, _tmpBinary));
        }
      }

      var extraZeroCount = 0;
      i = 0;
      len = binaryArray.length;
      for (; i < len; i += 6) {
        var diff = (i + 6) - len;
        if (diff == 2) {
          extraZeroCount = 2;
        } else if (diff == 4) {
          extraZeroCount = 4;
        }
        // if(extra_Zero_Count > 0){
        //  len += extra_Zero_Count+1;
        // }
        var _tmpExtraZeroCount = extraZeroCount;
        while (--_tmpExtraZeroCount >= 0) {
          binaryArray.push(0);
        }
        base64Index.push(_toDecimal(binaryArray.slice(i, i + 6)));
      }

      var base64 = '';
      i = 0;
      len = base64Index.length;
      for (; i < len; ++i) {
        base64 += BASE64_MAPPING[base64Index[i]];
      }

      i = 0;
      len = extraZeroCount / 2;
      for (; i < len; ++i) {
        base64 += '=';
      }
      return base64;
    },

    /**
     *BASE64  Decode for UTF-8
     */
    decode: function (_base64Str) {
      var _len = _base64Str.length;
      var extraZeroCount = 0;
      /**
       *计算在进行BASE64编码的时候，补了几个0
       */
      if (_base64Str.charAt(_len - 1) == '=') {
        if (_base64Str.charAt(_len - 2) == '=') { // 两个等号说明补了4个0
          extraZeroCount = 4;
          _base64Str = _base64Str.substring(0, _len - 2);
        } else { // 一个等号说明补了2个0
          extraZeroCount = 2;
          _base64Str = _base64Str.substring(0, _len - 1);
        }
      }

      var binaryArray = [];
      var i = 0, len = _base64Str.length;
      for (; i < len; ++i) {
        var c = _base64Str.charAt(i);
        for (var j = 0, size = BASE64_MAPPING.length; j < size; ++j) {
          if (c == BASE64_MAPPING[j]) {
            var _tmp = _toBinary(j);
            /* 不足6位的补0*/
            var _tmpLen = _tmp.length;
            if (6 - _tmpLen > 0) {
              for (var k = 6 - _tmpLen; k > 0; --k) {
                _tmp.unshift(0);
              }
            }
            binaryArray = binaryArray.concat(_tmp);
            break;
          }
        }
      }

      if (extraZeroCount > 0) {
        binaryArray = binaryArray.slice(0, binaryArray.length - extraZeroCount);
      }

      var unicode = [];
      var unicodeBinary = [];
      i = 0;
      len = binaryArray.length;
      for (; i < len;) {
        if (binaryArray[i] == 0) {
          unicode = unicode.concat(_toDecimal(binaryArray.slice(i, i + 8)));
          i += 8;
        } else {
          var sum = 0;
          while (i < len) {
            if (binaryArray[i] == 1) {
              ++sum;
            } else {
              break;
            }
            ++i;
          }
          unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 1, i + 8 - sum));
          i += 8 - sum;
          while (sum > 1) {
            unicodeBinary = unicodeBinary.concat(binaryArray.slice(i + 2, i + 8));
            i += 8;
            --sum;
          }
          unicode = unicode.concat(_toDecimal(unicodeBinary));
          unicodeBinary = [];
        }
      }

      var str = '';
      i = 0;
      len = unicode.length;
      for (; i < len; ++i) {
        str += String.fromCharCode(unicode[i]);
      }
      return str;
    }
  };
  return __BASE64;
}));